Well, you're running two applets that graphically display stuff to watch load and CPU; I'd try disabling those and monitoring it with a script that loops, dumping data to a file (so as not even to incur CPU load for network traffic ala ssh) and see if it does settle. Keep in mind that the waking up to run the applets might occur before it samples the CPU... it could be 164 99% of the time. (Which of course applies to any method of measuring it...)